{"id":25269,"date":"2020-04-06T07:31:00","date_gmt":"2020-04-06T07:31:00","guid":{"rendered":"https:\/\/www.bgs.ac.uk\/?page_id=25269"},"modified":"2021-06-14T08:14:47","modified_gmt":"2021-06-14T08:14:47","slug":"landslides","status":"publish","type":"page","link":"https:\/\/www.bgs.ac.uk\/discovering-geology\/earth-hazards\/landslides\/","title":{"rendered":"Understanding landslides"},"content":{"rendered":"\t\t\t<section class=\"hero-section hero-section-with-social\">\n\t\t\t\t\t\t\t\t<div class=\"hero-info-wrap\">\n\t\t\t\t\t<div class=\"container\">\n\t\t\t\t\t\t<div class=\"row\">\n\t\t\t\t\t\t\t<div class=\"col-12\">\n\t\t\t\t\t\t\t\t<div class=\"hero-info\">\n\t\t\t\t\t\t\t\t\t<h1>Understanding landslides<\/h1>\n\t\t\t\t\t\t\t\t\t<p>Discovering Geology &mdash; Earth hazards<\/p>\t\t\t\t\t\t\t\t<\/div>\n\t\t\t\t\t\t\t<\/div>\n\t\t\t\t\t\t<\/div>\n\t\t\t\t\t<\/div>\n\t\t\t\t<\/div>\n\t\t\t\t\t\t\t\t\n\t\t\t<div class=\"social-wrap social-wrap-inline-them\">\n\t\t\t\t<div class=\"sea-background-f\">\n\t\t\t\t\t<span>Share this article<\/span><a target=\"_blank\"  href=\"https:\/\/www.facebook.com\/sharer\/sharer.php?u=https:\/\/www.bgs.ac.uk\/discovering-geology\/earth-hazards\/landslides\/\"><span class=\"icon-facebook\"><span class=\"hidden\">Facebook<\/span><\/span><\/a><a target=\"_blank\"  href=\"https:\/\/twitter.com\/intent\/tweet?text=Understanding%20landslides&#038;url=https:\/\/www.bgs.ac.uk\/discovering-geology\/earth-hazards\/landslides\/\"><span class=\"icon-twitter\"><span class=\"hidden\">Twitter<\/span><\/span><\/a><a   onclick=\"javascript:void( (function() {var e=document.createElement('script' );e.setAttribute('type','text\/javascript' );e.setAttribute('charset','UTF-8' );e.setAttribute('src','\/\/assets.pinterest.com\/js\/pinmarklet.js?r='+Math.random()*99999999);document.body.appendChild(e)})());\"  href=\"javascript:void(0);\"><span class=\"icon-pinterest\"><span class=\"hidden\">Pinterest<\/span><\/span><\/a><a target=\"_blank\"  href=\"https:\/\/wa.me?text=https:\/\/www.bgs.ac.uk\/discovering-geology\/earth-hazards\/landslides\/\"><span class=\"icon-whatsapp\"><span class=\"hidden\">WhatsApp<\/span><\/span><\/a><a   href=\"mailto:?subject=Understanding%20landslides&#038;body=What%20is%20a%20landslide?%20Why%20do%20landslides%20happen?%20How%20to%20classify%20a%20landslide.%20Landslides%20in%20the%20UK%20and%20around%20the%20world.%20%20(https:\/\/www.bgs.ac.uk\/discovering-geology\/earth-hazards\/landslides\/)\"><span class=\"icon-mail\"><span class=\"hidden\">Email<\/span><\/span><\/a><a href=\"#\" data-copy=\"https:\/\/www.bgs.ac.uk\/discovering-geology\/earth-hazards\/landslides\/\" class=\"copy-url-on-click\"><span class=\"icon-link\"><span class=\"hidden\">Copy Link<\/span><\/span><\/a><\/div><\/div>\t\t\t\t\t\t\t\t\t<div class=\"img-wrap\">\n\t\t\t\t\t\t\t<img decoding=\"async\" src=\"https:\/\/www.bgs.ac.uk\/wp-content\/uploads\/2021\/06\/P757469-150x150.jpg\" class=\"lazy-blur hero-img\" alt=\"P757469\" data-src=\"https:\/\/www.bgs.ac.uk\/wp-content\/uploads\/2021\/06\/P757469.jpg\" \/>\t\t\t\t\t<\/div>\n\t\t\t\t\t\t\t<\/section>\n\t\t\t\n\n\n<section class=\"wp-block-bgs-blocks-content-container content-section\"><div class=\"container\"><div class=\"row\"><div class=\"col-12\">\n<h2 class=\"wp-block-heading\" id=\"what\">What is a landslide?<\/h2>\n\n\n\n<p>A landslide is a mass movement of material, such as rock, earth or debris, down a slope. They can happen suddenly or more slowly over long periods of time. <\/p>\n\n\n\n<p>When the force of gravity acting on a slope exceeds the resisting forces of a slope, the slope will fail and a landslide occurs. External factors can lead to landslides happening, including:  <\/p>\n\n\n\n<ul><li>heavy rainfall leading to saturation of the ground<\/li><li>erosion of the base of a slope <\/li><li>changes to the material&#8217;s strength through weathering <\/li><\/ul>\n\n\n<figure  class=\"img-wrap\"><a href=\"https:\/\/www.bgs.ac.uk\/wp-content\/uploads\/2020\/04\/Pennington_point_rockfall_P770831.jpg\" data-toggle=\"lightbox\" data-footer=\"&lt;p&gt;Rock fall landslide at Pennington Point, near Sidmouth on the south-east Devon coast, UK. \u00a9 Eve Mathews, used with kind permission. All rights reserved.&lt;\/p&gt;\n\" data-gallery=\"gallery_75019\"><img decoding=\"async\" src=\"https:\/\/www.bgs.ac.uk\/wp-content\/uploads\/2020\/04\/Pennington_point_rockfall_P770831-150x150.jpg\" class=\"lazy-blur\" alt=\"Rock fall landslide at Pennington Point, Sidmouth\" data-src=\"https:\/\/www.bgs.ac.uk\/wp-content\/uploads\/2020\/04\/Pennington_point_rockfall_P770831-960x497.jpg\" \/><\/a><figcaption class=\"caption \">\n\t\t\t\t\t<div class=\"caption-icon\">\n\t\t\t\t\t\t<img decoding=\"async\" src=\"https:\/\/www.bgs.ac.uk\/wp-content\/themes\/bgs\/img\/info-caption.svg\" alt=\"Information icon\">\n\t\t\t\t\t<\/div>\n\t\t\t\t\t<div class=\"caption-text\"><p>Rock fall landslide at Pennington Point, near Sidmouth on the south-east Devon coast, UK. \u00a9 Eve Mathews, used with kind permission. All rights reserved.<\/p>\n<\/div>\n\t\t\t\t\t<div class=\"expand-box expand-box-top\"><a href=\"https:\/\/www.bgs.ac.uk\/wp-content\/uploads\/2020\/04\/Pennington_point_rockfall_P770831.jpg\" data-toggle=\"lightbox\" data-footer=\"&lt;p&gt;Rock fall landslide at Pennington Point, near Sidmouth on the south-east Devon coast, UK. \u00a9 Eve Mathews, used with kind permission. All rights reserved.&lt;\/p&gt;\n\" data-gallery=\"gallery_75019\"><img decoding=\"async\" src=\"https:\/\/www.bgs.ac.uk\/wp-content\/themes\/bgs\/img\/expand.svg\" alt=\"Expand icon\"><\/a><\/div>\n\t\t\t\t<\/figcaption><\/figure>\n\n\n<p>Landslides are classified by their type of movement. The four main types of movement are: <\/p>\n\n\n\n<ul><li><a href=\"https:\/\/www.bgs.ac.uk\/discovering-geology\/earth-hazards\/landslides\/how-to-classify-a-landslide\/#falls\">falls<\/a><\/li><li><a href=\"https:\/\/www.bgs.ac.uk\/discovering-geology\/earth-hazards\/landslides\/how-to-classify-a-landslide\/#topples\">topples<\/a><\/li><li><a href=\"https:\/\/www.bgs.ac.uk\/discovering-geology\/earth-hazards\/landslides\/how-to-classify-a-landslide\/#slides\">slides<\/a> (rotational and translational) <\/li><li><a href=\"https:\/\/www.bgs.ac.uk\/discovering-geology\/earth-hazards\/landslides\/how-to-classify-a-landslide\/#flows\">flows<\/a><\/li><\/ul>\n\n\n\n<p>Landslides can be classified as just one of these movements or, more commonly, can be a mixture of several.<\/p>\n\n\n\n<p>At BGS we usually study the landslides that happen in&nbsp;<a href=\"https:\/\/www.bgs.ac.uk\/discovering-geology\/earth-hazards\/landslides\/landslides-in-the-uk-and-around-the-world\/#uk\">the UK<\/a>, but here we also include some examples of large landslides that have occurred elsewhere&nbsp;<a href=\"https:\/\/www.bgs.ac.uk\/discovering-geology\/earth-hazards\/landslides\/landslides-in-the-uk-and-around-the-world\/#world\">around the world<\/a>&nbsp;and also&nbsp;<a href=\"https:\/\/www.bgs.ac.uk\/discovering-geology\/earth-hazards\/landslides\/landslides-in-the-uk-and-around-the-world\/#inthesea\">in the sea<\/a>.<\/p>\n\n\n\n<h2 class=\"wp-block-heading\" id=\"why\">Why do landslides happen?<\/h2>\n\n\n\n<p>A landslide may occur because the strength of the material is weakened. This reduces the power of the &#8216;glue&#8217; that cements the rock or soil grains together. Located on a slope, the rock is then no longer strong enough to resist the forces of gravity acting upon it.<\/p>\n\n\n<figure  class=\"img-wrap\"><a href=\"https:\/\/www.bgs.ac.uk\/wp-content\/uploads\/2020\/04\/BournemouthLandslide2016_website.jpg\" data-toggle=\"lightbox\" data-footer=\"&lt;p&gt;On 24 April 2016, a landslide at East Cliff, Bournemouth caused damage to a funicular railway, a toilet block and an array of fences and benches that were at the top of the cliff. BGS \u00a9 UKRI.&lt;\/p&gt;\n\" data-gallery=\"gallery_50574\"><img decoding=\"async\" src=\"https:\/\/www.bgs.ac.uk\/wp-content\/uploads\/2020\/04\/BournemouthLandslide2016_website-150x150.jpg\" class=\"lazy-blur\" alt=\"Landslide at East Cliff, Bournemouth\" data-src=\"https:\/\/www.bgs.ac.uk\/wp-content\/uploads\/2020\/04\/BournemouthLandslide2016_website.jpg\" \/><\/a><figcaption class=\"caption \">\n\t\t\t\t\t<div class=\"caption-icon\">\n\t\t\t\t\t\t<img decoding=\"async\" src=\"https:\/\/www.bgs.ac.uk\/wp-content\/themes\/bgs\/img\/info-caption.svg\" alt=\"Information icon\">\n\t\t\t\t\t<\/div>\n\t\t\t\t\t<div class=\"caption-text\"><p>On 24 April 2016, a landslide at East Cliff, Bournemouth caused damage to a funicular railway, a toilet block and an array of fences and benches that were at the top of the cliff. BGS \u00a9 UKRI.<\/p>\n<\/div>\n\t\t\t\t\t<div class=\"expand-box expand-box-top\"><a href=\"https:\/\/www.bgs.ac.uk\/wp-content\/uploads\/2020\/04\/BournemouthLandslide2016_website.jpg\" data-toggle=\"lightbox\" data-footer=\"&lt;p&gt;On 24 April 2016, a landslide at East Cliff, Bournemouth caused damage to a funicular railway, a toilet block and an array of fences and benches that were at the top of the cliff. BGS \u00a9 UKRI.&lt;\/p&gt;\n\" data-gallery=\"gallery_50574\"><img decoding=\"async\" src=\"https:\/\/www.bgs.ac.uk\/wp-content\/themes\/bgs\/img\/expand.svg\" alt=\"Expand icon\"><\/a><\/div>\n\t\t\t\t<\/figcaption><\/figure>\n\n\n<h2 class=\"wp-block-heading\" id=\"chances\">What can increase the chance of a landslide?<\/h2>\n\n\n\n<p>Several factors can increase a slope&#8217;s susceptibility to a landslide event.<\/p>\n\n\n\n<ul><li>Water: adding water to the material on a slope makes a landslide more likely to happen. This is because water adds weight, lowers the strength of the material and reduces friction, making it easier for material to move downslope.<\/li><li>Erosion processes: if the bottom of a slope is continually eroded, for example by the sea or a river, the slope will eventually become too steep to hold itself up.<\/li><li>Slope angle (steepness of slope): the slope angle is a key factor as far as landslides are concerned.\u00a0 Any change to this that makes it steeper (such as coastal erosion) increases the likelihood of a landslide.<\/li><li>Rock type: the type of rocks in the slope, and their combination, can increase the chance of a landslide.<\/li><li>Grain shape: the shape of the grains that make up a rock can affect the risk of a landslide.<\/li><li>Jointing and orientation of bedding planes.<\/li><li>Arrangement of the rock layers.<\/li><li>Weathering processes: for example freeze-thaw reduces the cohesion (&#8216;stickiness&#8217;) between the rock grains.<\/li><li>Vegetation: vegetation helps bind material together; removing vegetation increases the chance of a landslide.<\/li><li>Flooding.<\/li><li><a href=\"https:\/\/www.bgs.ac.uk\/discovering-geology\/earth-hazards\/volcanoes\/\">Volcanoes<\/a>\u00a0and\u00a0<a href=\"https:\/\/www.bgs.ac.uk\/discovering-geology\/earth-hazards\/earthquakes\/\">earthquake<\/a>\u00a0activity nearby.<\/li><li>Human activity: mining, traffic vibrations or urbanisation change surface water drainage patterns.<\/li><\/ul>\n\n\n<figure  class=\"img-wrap\"><a href=\"https:\/\/www.bgs.ac.uk\/wp-content\/uploads\/2020\/04\/debris_flow_restandbethankfulpass_P785354.jpg\" data-toggle=\"lightbox\" data-footer=\"&lt;p&gt;Following a period of heavy rain, a debris flow landslide occurred along the A83 Rest and Be Thankful pass (Argyll and Bute, Scotland) on 1 August 2012. It was reported that between 50 and 100 tonnes of material blocked the road, which was subsequently closed in both directions resulting in a long diversion. BGS \u00a9 UKRI.&lt;\/p&gt;\n\" data-gallery=\"gallery_35786\"><img decoding=\"async\" src=\"https:\/\/www.bgs.ac.uk\/wp-content\/uploads\/2020\/04\/debris_flow_restandbethankfulpass_P785354-150x150.jpg\" class=\"lazy-blur\" alt=\"Debris flow landslide on the A83\" data-src=\"https:\/\/www.bgs.ac.uk\/wp-content\/uploads\/2020\/04\/debris_flow_restandbethankfulpass_P785354-960x497.jpg\" \/><\/a><figcaption class=\"caption \">\n\t\t\t\t\t<div class=\"caption-icon\">\n\t\t\t\t\t\t<img decoding=\"async\" src=\"https:\/\/www.bgs.ac.uk\/wp-content\/themes\/bgs\/img\/info-caption.svg\" alt=\"Information icon\">\n\t\t\t\t\t<\/div>\n\t\t\t\t\t<div class=\"caption-text\"><p>Following a period of heavy rain, a debris flow landslide occurred along the A83 Rest and Be Thankful pass (Argyll and Bute, Scotland) on 1 August 2012. It was reported that between 50 and 100 tonnes of material blocked the road, which was subsequently closed in both directions resulting in a long diversion. BGS \u00a9 UKRI.<\/p>\n<\/div>\n\t\t\t\t\t<div class=\"expand-box expand-box-top\"><a href=\"https:\/\/www.bgs.ac.uk\/wp-content\/uploads\/2020\/04\/debris_flow_restandbethankfulpass_P785354.jpg\" data-toggle=\"lightbox\" data-footer=\"&lt;p&gt;Following a period of heavy rain, a debris flow landslide occurred along the A83 Rest and Be Thankful pass (Argyll and Bute, Scotland) on 1 August 2012. It was reported that between 50 and 100 tonnes of material blocked the road, which was subsequently closed in both directions resulting in a long diversion. BGS \u00a9 UKRI.&lt;\/p&gt;\n\" data-gallery=\"gallery_35786\"><img decoding=\"async\" src=\"https:\/\/www.bgs.ac.uk\/wp-content\/themes\/bgs\/img\/expand.svg\" alt=\"Expand icon\"><\/a><\/div>\n\t\t\t\t<\/figcaption><\/figure><\/div><\/div><\/div><\/section>\n\n\n\t\t\t\t\t<section   id=\"latest-content-2006-block_5f01c5b98e387\" class=\"cards-carousel-section  rock-background-d   \" >\n\t\t\t\t\t\t<div class=\"container\">\n\t\t\t\t\t\t\t\t\t\t\t\t\t<div class=\"row header-of-section\">\n\t\t\t\t\t\t\t\t<div class=\"col-12\">\n\t\t\t\t\t\t\t\t\t<h2>Further information on landslides<\/h2>\n\t\t\t\t\t\t\t\t<\/div>\n\t\t\t\t\t\t\t<\/div>\n\t\t\t\t\t\t\t\t\t\t\t\t\t\t<div class=\"row \">\n\t\t\t\t\t\t\t<div class=\"col-12 owl-carousel carousel-basic-2-color owl-theme carousel-js\">\t\t\t\t\t\t\t<div class=\"item cards  cards-find-more  \">\n\t\t<a href=\"https:\/\/www.bgs.ac.uk\/geology-projects\/landslides\/landslide-case-studies\/\" class=\"media-wrap\">\n\t\t<img decoding=\"async\" src=\"https:\/\/www.bgs.ac.uk\/wp-content\/uploads\/2020\/02\/pennington_feature_P761259-150x150.jpg\" class=\"lazy-blur wp-post-image\" alt=\"fall at Pennington Point. (Photo: \u00a9 Eve Mathews)\" data-src=\"https:\/\/www.bgs.ac.uk\/wp-content\/uploads\/2020\/02\/pennington_feature_P761259.jpg\" \/>\t<\/a>\n\t\t<div class=\"info-wrap\">\n\t\t<div class=\"info\">\n\t\t\t<div><\/div>\n\t\t\t<h4><a href=\"https:\/\/www.bgs.ac.uk\/geology-projects\/landslides\/landslide-case-studies\/\">Landslide case studies<\/a><\/h4>\n\t\t\t\t\t\t\t\t\t\t<p>The landslides team at the BGS has studied numerous landslides. This work informs our geological maps, memoirs and sheet explanations and provides data for our National Landslide Database, which underpins much of our research.<\/p>\n\t\t\t\t\t<\/div>\n\t\t<a href=\"https:\/\/www.bgs.ac.uk\/geology-projects\/landslides\/landslide-case-studies\/\">Show more<\/a>\n\t<\/div>\n<\/div>\n<div class=\"item cards  cards-find-more  \">\n\t\t<a href=\"https:\/\/www.bgs.ac.uk\/geology-projects\/landslides\/landslides-and-rainfall\/\" class=\"media-wrap\">\n\t\t<img decoding=\"async\" src=\"https:\/\/www.bgs.ac.uk\/wp-content\/uploads\/2020\/05\/feature_landslides-150x150.jpg\" class=\"lazy-blur wp-post-image\" alt=\"landslides and rainfall\" data-src=\"https:\/\/www.bgs.ac.uk\/wp-content\/uploads\/2020\/05\/feature_landslides.jpg\" \/>\t<\/a>\n\t\t<div class=\"info-wrap\">\n\t\t<div class=\"info\">\n\t\t\t<div><\/div>\n\t\t\t<h4><a href=\"https:\/\/www.bgs.ac.uk\/geology-projects\/landslides\/landslides-and-rainfall\/\">Landslides and rainfall<\/a><\/h4>\n\t\t\t\t\t\t\t\t\t\t<p>We combine rainfall statistics and landslide data to produce graphs demonstrating the relationship between landslides and rainfall.<\/p>\n\t\t\t\t\t<\/div>\n\t\t<a href=\"https:\/\/www.bgs.ac.uk\/geology-projects\/landslides\/landslides-and-rainfall\/\">Show more<\/a>\n\t<\/div>\n<\/div>\n<div class=\"item cards  cards-find-more  \">\n\t\t<a href=\"https:\/\/www.bgs.ac.uk\/geology-projects\/landslides\/national-landslide-database\/\" class=\"media-wrap\">\n\t\t<img decoding=\"async\" src=\"https:\/\/www.bgs.ac.uk\/wp-content\/uploads\/2020\/03\/Feature_landslides_db-150x150.jpg\" class=\"lazy-blur wp-post-image\" alt=\"National Landslides Database\" data-src=\"https:\/\/www.bgs.ac.uk\/wp-content\/uploads\/2020\/03\/Feature_landslides_db.jpg\" \/>\t<\/a>\n\t\t<div class=\"info-wrap\">\n\t\t<div class=\"info\">\n\t\t\t<div><\/div>\n\t\t\t<h4><a href=\"https:\/\/www.bgs.ac.uk\/geology-projects\/landslides\/national-landslide-database\/\">National Landslide Database<\/a><\/h4>\n\t\t\t\t\t\t\t\t\t\t<p>The BGS National Landslide Database (NLD) is the most extensive source of information on landslides in Great Britain.<\/p>\n\t\t\t\t\t<\/div>\n\t\t<a href=\"https:\/\/www.bgs.ac.uk\/geology-projects\/landslides\/national-landslide-database\/\">Show more<\/a>\n\t<\/div>\n<\/div>\n<div class=\"item cards  cards-find-more  \">\n\t\t<a href=\"https:\/\/www.bgs.ac.uk\/geology-projects\/landslides\/landslide-observatories\/\" class=\"media-wrap\">\n\t\t<img decoding=\"async\" src=\"https:\/\/www.bgs.ac.uk\/wp-content\/uploads\/2020\/05\/Aldbrough_website_feature-150x150.jpg\" class=\"lazy-blur wp-post-image\" alt=\"Aldbrough Coastal Landslide Observatory.\" data-src=\"https:\/\/www.bgs.ac.uk\/wp-content\/uploads\/2020\/05\/Aldbrough_website_feature.jpg\" \/>\t<\/a>\n\t\t<div class=\"info-wrap\">\n\t\t<div class=\"info\">\n\t\t\t<div><\/div>\n\t\t\t<h4><a href=\"https:\/\/www.bgs.ac.uk\/geology-projects\/landslides\/landslide-observatories\/\">Landslide observatories<\/a><\/h4>\n\t\t\t\t\t\t\t\t\t\t<p>BGS have long-term monitoring observatories where data have been collected, in some instances, since 2001.<\/p>\n\t\t\t\t\t<\/div>\n\t\t<a href=\"https:\/\/www.bgs.ac.uk\/geology-projects\/landslides\/landslide-observatories\/\">Show more<\/a>\n\t<\/div>\n<\/div>\n<div class=\"item cards  cards-find-more  \">\n\t\t<a href=\"https:\/\/www.bgs.ac.uk\/discovering-geology\/earth-hazards\/landslides\/landslides-in-the-uk-and-around-the-world\/\" class=\"media-wrap\">\n\t\t<img decoding=\"async\" src=\"https:\/\/www.bgs.ac.uk\/wp-content\/uploads\/2020\/04\/Storegga_landslide_website_feature-150x150.jpg\" class=\"lazy-blur wp-post-image\" alt=\"Storegga landslide\" data-src=\"https:\/\/www.bgs.ac.uk\/wp-content\/uploads\/2020\/04\/Storegga_landslide_website_feature.jpg\" \/>\t<\/a>\n\t\t<div class=\"info-wrap\">\n\t\t<div class=\"info\">\n\t\t\t<div><\/div>\n\t\t\t<h4><a href=\"https:\/\/www.bgs.ac.uk\/discovering-geology\/earth-hazards\/landslides\/landslides-in-the-uk-and-around-the-world\/\">Landslides in the UK and around the world<\/a><\/h4>\n\t\t\t\t\t\t\t\t\t\t<p>Landslides in the UK, around the world and under the sea.<\/p>\n\t\t\t\t\t<\/div>\n\t\t<a href=\"https:\/\/www.bgs.ac.uk\/discovering-geology\/earth-hazards\/landslides\/landslides-in-the-uk-and-around-the-world\/\">Show more<\/a>\n\t<\/div>\n<\/div>\n<div class=\"item cards  cards-find-more  \">\n\t\t<a href=\"https:\/\/www.bgs.ac.uk\/discovering-geology\/earth-hazards\/landslides\/how-to-classify-a-landslide\/\" class=\"media-wrap\">\n\t\t<img decoding=\"async\" src=\"https:\/\/www.bgs.ac.uk\/wp-content\/uploads\/2020\/04\/holbeck_hall_feature-150x150.jpg\" class=\"lazy-blur wp-post-image\" alt=\"Holbeck Hall Landslide\" data-src=\"https:\/\/www.bgs.ac.uk\/wp-content\/uploads\/2020\/04\/holbeck_hall_feature.jpg\" \/>\t<\/a>\n\t\t<div class=\"info-wrap\">\n\t\t<div class=\"info\">\n\t\t\t<div><\/div>\n\t\t\t<h4><a href=\"https:\/\/www.bgs.ac.uk\/discovering-geology\/earth-hazards\/landslides\/how-to-classify-a-landslide\/\">How to classify a landslide<\/a><\/h4>\n\t\t\t\t\t\t\t\t\t\t<p>Landslides are classified by their type of movement. The four main types of movement are falls, topples, slides and flows. <\/p>\n\t\t\t\t\t<\/div>\n\t\t<a href=\"https:\/\/www.bgs.ac.uk\/discovering-geology\/earth-hazards\/landslides\/how-to-classify-a-landslide\/\">Show more<\/a>\n\t<\/div>\n<\/div>\n<\/div>\t\t\t\t\t\t\t<\/div>\n\t\t\t\t\t\t\t\t\t\t\t\t\t\t<div class=\"row\">\n\t\t\t\t\t\t\t\t<div class=\"col-12\">\n\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t<\/div>\n\t\t\t\t\t\t\t<\/div>\n\t\t\t\t\t\t\t\t\t\t\t\t\t<\/div>\n\t\t\t\t\t<\/section>\n\t\t\t\t\n\n\t\t\t\t\t<section   id=\"latest-content-7615-block_5efc6752084ed\" class=\"grid-section  primary-background   \" >\n\t\t\t\t\t\t<div class=\"container\">\n\t\t\t\t\t\t\t\t\t\t\t\t\t<div class=\"row header-of-section\">\n\t\t\t\t\t\t\t\t<div class=\"col-12\">\n\t\t\t\t\t\t\t\t\t<h2>You may also be interested in<\/h2>\n\t\t\t\t\t\t\t\t<\/div>\n\t\t\t\t\t\t\t<\/div>\n\t\t\t\t\t\t\t\t\t\t\t\t\t\t<div class=\"row grid-wrap\">\n\t\t\t\t\t\t\t\t\t\t\t\t\t\t<div class=\"col-lg-6 col-12\">\n\t<div class=\"cards cards-orizontal-sm  cards-find-more  cards-bordered\">\n\t\t\t\t<a href=\"https:\/\/www.bgs.ac.uk\/discovering-geology\/\" class=\"media-wrap\">\n\t\t\t<img decoding=\"async\" src=\"https:\/\/www.bgs.ac.uk\/wp-content\/uploads\/2020\/04\/feature_homepage_p815563-150x150.jpg\" class=\"lazy-blur wp-post-image\" alt=\"Ammonite p815563\" data-src=\"https:\/\/www.bgs.ac.uk\/wp-content\/uploads\/2020\/04\/feature_homepage_p815563.jpg\" \/>\t\t\t\t\t<\/a>\n\t\t\t\t<div class=\"info-wrap\">\n\t\t\t<div class=\"info\">\n\t\t\t\t<h4><a href=\"https:\/\/www.bgs.ac.uk\/discovering-geology\/\">Discovering Geology<\/a><\/h4>\n\t\t\t\t\t\t\t\t\t\t\t\t\t<p>Discovering Geology introduces a range of geoscience topics to school-age students and learners of all ages.<\/p>\n\t\t\t\t\t\t\t<\/div>\n\t\t\t<a href=\"https:\/\/www.bgs.ac.uk\/discovering-geology\/\">Show more<\/a>\n\t\t<\/div>\n\t<\/div>\n<\/div>\n<div class=\"col-lg-6 col-12\">\n\t<div class=\"cards cards-orizontal-sm  cards-find-more  cards-bordered\">\n\t\t\t\t<a href=\"https:\/\/www.bgs.ac.uk\/discovering-geology\/earth-hazards\/\" class=\"media-wrap\">\n\t\t\t<img decoding=\"async\" src=\"https:\/\/www.bgs.ac.uk\/wp-content\/uploads\/2020\/05\/feature_hazards_pexels_235807-150x150.jpg\" class=\"lazy-blur wp-post-image\" alt=\"lava flow - Pexels \/ Pixabay\" data-src=\"https:\/\/www.bgs.ac.uk\/wp-content\/uploads\/2020\/05\/feature_hazards_pexels_235807.jpg\" \/>\t\t\t\t\t<\/a>\n\t\t\t\t<div class=\"info-wrap\">\n\t\t\t<div class=\"info\">\n\t\t\t\t<h4><a href=\"https:\/\/www.bgs.ac.uk\/discovering-geology\/earth-hazards\/\">Earth hazards<\/a><\/h4>\n\t\t\t\t\t\t\t\t\t\t\t\t\t<p>The Earth beneath our feet is constantly shifting and moving,  and violently with catastrophic and immediate results. Find out more about earth hazards.<\/p>\n\t\t\t\t\t\t\t<\/div>\n\t\t\t<a href=\"https:\/\/www.bgs.ac.uk\/discovering-geology\/earth-hazards\/\">Show more<\/a>\n\t\t<\/div>\n\t<\/div>\n<\/div>\n\t\t\t\t\t\t\t<\/div>\n\t\t\t\t\t\t\t\t\t\t\t\t\t\t<div class=\"row\">\n\t\t\t\t\t\t\t\t<div class=\"col-12\">\n\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t<\/div>\n\t\t\t\t\t\t\t<\/div>\n\t\t\t\t\t\t\t\t\t\t\t\t\t<\/div>\n\t\t\t\t\t<\/section>\n\t\t\t\t","protected":false},"excerpt":{"rendered":"<p>What is a landslide? Why do landslides happen? How to classify a landslide. Landslides in the UK and around the world. <\/p>\n","protected":false},"author":2,"featured_media":28249,"parent":3863,"menu_order":3,"comment_status":"closed","ping_status":"closed","template":"","meta":{"_acf_changed":false,"_relevanssi_hide_post":"","_relevanssi_hide_content":"","_relevanssi_pin_for_all":"on","_relevanssi_pin_keywords":"landslides","_relevanssi_unpin_keywords":"","_relevanssi_related_keywords":"","_relevanssi_related_include_ids":"","_relevanssi_related_exclude_ids":"","_relevanssi_related_no_append":"","_relevanssi_related_not_related":"","_relevanssi_related_posts":"33255,33594,8334,8160,34185,34330","_relevanssi_noindex_reason":"","footnotes":""},"tags":[],"acf":[],"yoast_head":"<!-- This site is optimized with the Yoast SEO plugin v22.3 - https:\/\/yoast.com\/wordpress\/plugins\/seo\/ -->\n<title>Understanding landslides - British Geological Survey<\/title>\n<meta name=\"description\" content=\"A landslide is a mass movement of material down the slope of a hill or cliff. They can happen suddenly or move slowly over long periods of time.\" \/>\n<meta name=\"robots\" content=\"index, follow, max-snippet:-1, max-image-preview:large, max-video-preview:-1\" \/>\n<link rel=\"canonical\" href=\"https:\/\/www.bgs.ac.uk\/discovering-geology\/earth-hazards\/landslides\/\" \/>\n<meta property=\"og:locale\" content=\"en_GB\" \/>\n<meta property=\"og:type\" content=\"article\" \/>\n<meta property=\"og:title\" content=\"Understanding landslides - British Geological Survey\" \/>\n<meta property=\"og:description\" content=\"A landslide is a mass movement of material down the slope of a hill or cliff. They can happen suddenly or move slowly over long periods of time.\" \/>\n<meta property=\"og:url\" content=\"https:\/\/www.bgs.ac.uk\/discovering-geology\/earth-hazards\/landslides\/\" \/>\n<meta property=\"og:site_name\" content=\"British Geological Survey\" \/>\n<meta property=\"article:modified_time\" content=\"2021-06-14T08:14:47+00:00\" \/>\n<meta property=\"og:image\" content=\"https:\/\/www.bgs.ac.uk\/wp-content\/uploads\/2020\/04\/debris_flow_restandbethankfulpass_P785354_feature.jpg\" \/>\n\t<meta property=\"og:image:width\" content=\"640\" \/>\n\t<meta property=\"og:image:height\" content=\"430\" \/>\n\t<meta property=\"og:image:type\" content=\"image\/jpeg\" \/>\n<meta name=\"twitter:card\" content=\"summary_large_image\" \/>\n<meta name=\"twitter:label1\" content=\"Estimated reading time\" \/>\n\t<meta name=\"twitter:data1\" content=\"2 minutes\" \/>\n<script type=\"application\/ld+json\" class=\"yoast-schema-graph\">{\"@context\":\"https:\/\/schema.org\",\"@graph\":[{\"@type\":\"WebPage\",\"@id\":\"https:\/\/www.bgs.ac.uk\/discovering-geology\/earth-hazards\/landslides\/\",\"url\":\"https:\/\/www.bgs.ac.uk\/discovering-geology\/earth-hazards\/landslides\/\",\"name\":\"Understanding landslides - British Geological Survey\",\"isPartOf\":{\"@id\":\"https:\/\/www.bgs.ac.uk\/#website\"},\"primaryImageOfPage\":{\"@id\":\"https:\/\/www.bgs.ac.uk\/discovering-geology\/earth-hazards\/landslides\/#primaryimage\"},\"image\":{\"@id\":\"https:\/\/www.bgs.ac.uk\/discovering-geology\/earth-hazards\/landslides\/#primaryimage\"},\"thumbnailUrl\":\"https:\/\/www.bgs.ac.uk\/wp-content\/uploads\/2020\/04\/debris_flow_restandbethankfulpass_P785354_feature.jpg\",\"datePublished\":\"2020-04-06T07:31:00+00:00\",\"dateModified\":\"2021-06-14T08:14:47+00:00\",\"description\":\"A landslide is a mass movement of material down the slope of a hill or cliff. They can happen suddenly or move slowly over long periods of time.\",\"breadcrumb\":{\"@id\":\"https:\/\/www.bgs.ac.uk\/discovering-geology\/earth-hazards\/landslides\/#breadcrumb\"},\"inLanguage\":\"en-GB\",\"potentialAction\":[{\"@type\":\"ReadAction\",\"target\":[\"https:\/\/www.bgs.ac.uk\/discovering-geology\/earth-hazards\/landslides\/\"]}]},{\"@type\":\"ImageObject\",\"inLanguage\":\"en-GB\",\"@id\":\"https:\/\/www.bgs.ac.uk\/discovering-geology\/earth-hazards\/landslides\/#primaryimage\",\"url\":\"https:\/\/www.bgs.ac.uk\/wp-content\/uploads\/2020\/04\/debris_flow_restandbethankfulpass_P785354_feature.jpg\",\"contentUrl\":\"https:\/\/www.bgs.ac.uk\/wp-content\/uploads\/2020\/04\/debris_flow_restandbethankfulpass_P785354_feature.jpg\",\"width\":640,\"height\":430,\"caption\":\"Following a period of heavy rain, on 1 August 2012 a debris flow landslide occurred along the A83 Rest and Be Thankful pass (Argyll and Bute, Scotland). It was reported that between 50 to 100 tonnes of material blocked the road that was subsequently closed in both directions resulting in a long diversion. BGS \u00a9UKRI. All rights reserved.\"},{\"@type\":\"BreadcrumbList\",\"@id\":\"https:\/\/www.bgs.ac.uk\/discovering-geology\/earth-hazards\/landslides\/#breadcrumb\",\"itemListElement\":[{\"@type\":\"ListItem\",\"position\":1,\"name\":\"Home\",\"item\":\"https:\/\/www.bgs.ac.uk\/\"},{\"@type\":\"ListItem\",\"position\":2,\"name\":\"Discovering Geology\",\"item\":\"https:\/\/www.bgs.ac.uk\/discovering-geology\/\"},{\"@type\":\"ListItem\",\"position\":3,\"name\":\"Earth hazards\",\"item\":\"https:\/\/www.bgs.ac.uk\/discovering-geology\/earth-hazards\/\"},{\"@type\":\"ListItem\",\"position\":4,\"name\":\"Understanding landslides\"}]},{\"@type\":\"WebSite\",\"@id\":\"https:\/\/www.bgs.ac.uk\/#website\",\"url\":\"https:\/\/www.bgs.ac.uk\/\",\"name\":\"British Geological Survey\",\"description\":\"World-leading geological solutions\",\"publisher\":{\"@id\":\"https:\/\/www.bgs.ac.uk\/#organization\"},\"potentialAction\":[{\"@type\":\"SearchAction\",\"target\":{\"@type\":\"EntryPoint\",\"urlTemplate\":\"https:\/\/www.bgs.ac.uk\/?s={search_term_string}\"},\"query-input\":\"required name=search_term_string\"}],\"inLanguage\":\"en-GB\"},{\"@type\":\"Organization\",\"@id\":\"https:\/\/www.bgs.ac.uk\/#organization\",\"name\":\"British Geological Survey\",\"url\":\"https:\/\/www.bgs.ac.uk\/\",\"logo\":{\"@type\":\"ImageObject\",\"inLanguage\":\"en-GB\",\"@id\":\"https:\/\/www.bgs.ac.uk\/#\/schema\/logo\/image\/\",\"url\":\"https:\/\/www.bgs.ac.uk\/wp-content\/uploads\/2020\/03\/BGS-logo-large.png\",\"contentUrl\":\"https:\/\/www.bgs.ac.uk\/wp-content\/uploads\/2020\/03\/BGS-logo-large.png\",\"width\":250,\"height\":104,\"caption\":\"British Geological Survey\"},\"image\":{\"@id\":\"https:\/\/www.bgs.ac.uk\/#\/schema\/logo\/image\/\"}}]}<\/script>\n<!-- \/ Yoast SEO plugin. -->","yoast_head_json":{"title":"Understanding landslides - British Geological Survey","description":"A landslide is a mass movement of material down the slope of a hill or cliff. They can happen suddenly or move slowly over long periods of time.","robots":{"index":"index","follow":"follow","max-snippet":"max-snippet:-1","max-image-preview":"max-image-preview:large","max-video-preview":"max-video-preview:-1"},"canonical":"https:\/\/www.bgs.ac.uk\/discovering-geology\/earth-hazards\/landslides\/","og_locale":"en_GB","og_type":"article","og_title":"Understanding landslides - British Geological Survey","og_description":"A landslide is a mass movement of material down the slope of a hill or cliff. They can happen suddenly or move slowly over long periods of time.","og_url":"https:\/\/www.bgs.ac.uk\/discovering-geology\/earth-hazards\/landslides\/","og_site_name":"British Geological Survey","article_modified_time":"2021-06-14T08:14:47+00:00","og_image":[{"width":640,"height":430,"url":"https:\/\/www.bgs.ac.uk\/wp-content\/uploads\/2020\/04\/debris_flow_restandbethankfulpass_P785354_feature.jpg","type":"image\/jpeg"}],"twitter_card":"summary_large_image","twitter_misc":{"Estimated reading time":"2 minutes"},"schema":{"@context":"https:\/\/schema.org","@graph":[{"@type":"WebPage","@id":"https:\/\/www.bgs.ac.uk\/discovering-geology\/earth-hazards\/landslides\/","url":"https:\/\/www.bgs.ac.uk\/discovering-geology\/earth-hazards\/landslides\/","name":"Understanding landslides - British Geological Survey","isPartOf":{"@id":"https:\/\/www.bgs.ac.uk\/#website"},"primaryImageOfPage":{"@id":"https:\/\/www.bgs.ac.uk\/discovering-geology\/earth-hazards\/landslides\/#primaryimage"},"image":{"@id":"https:\/\/www.bgs.ac.uk\/discovering-geology\/earth-hazards\/landslides\/#primaryimage"},"thumbnailUrl":"https:\/\/www.bgs.ac.uk\/wp-content\/uploads\/2020\/04\/debris_flow_restandbethankfulpass_P785354_feature.jpg","datePublished":"2020-04-06T07:31:00+00:00","dateModified":"2021-06-14T08:14:47+00:00","description":"A landslide is a mass movement of material down the slope of a hill or cliff. They can happen suddenly or move slowly over long periods of time.","breadcrumb":{"@id":"https:\/\/www.bgs.ac.uk\/discovering-geology\/earth-hazards\/landslides\/#breadcrumb"},"inLanguage":"en-GB","potentialAction":[{"@type":"ReadAction","target":["https:\/\/www.bgs.ac.uk\/discovering-geology\/earth-hazards\/landslides\/"]}]},{"@type":"ImageObject","inLanguage":"en-GB","@id":"https:\/\/www.bgs.ac.uk\/discovering-geology\/earth-hazards\/landslides\/#primaryimage","url":"https:\/\/www.bgs.ac.uk\/wp-content\/uploads\/2020\/04\/debris_flow_restandbethankfulpass_P785354_feature.jpg","contentUrl":"https:\/\/www.bgs.ac.uk\/wp-content\/uploads\/2020\/04\/debris_flow_restandbethankfulpass_P785354_feature.jpg","width":640,"height":430,"caption":"Following a period of heavy rain, on 1 August 2012 a debris flow landslide occurred along the A83 Rest and Be Thankful pass (Argyll and Bute, Scotland). It was reported that between 50 to 100 tonnes of material blocked the road that was subsequently closed in both directions resulting in a long diversion. BGS \u00a9UKRI. All rights reserved."},{"@type":"BreadcrumbList","@id":"https:\/\/www.bgs.ac.uk\/discovering-geology\/earth-hazards\/landslides\/#breadcrumb","itemListElement":[{"@type":"ListItem","position":1,"name":"Home","item":"https:\/\/www.bgs.ac.uk\/"},{"@type":"ListItem","position":2,"name":"Discovering Geology","item":"https:\/\/www.bgs.ac.uk\/discovering-geology\/"},{"@type":"ListItem","position":3,"name":"Earth hazards","item":"https:\/\/www.bgs.ac.uk\/discovering-geology\/earth-hazards\/"},{"@type":"ListItem","position":4,"name":"Understanding landslides"}]},{"@type":"WebSite","@id":"https:\/\/www.bgs.ac.uk\/#website","url":"https:\/\/www.bgs.ac.uk\/","name":"British Geological Survey","description":"World-leading geological solutions","publisher":{"@id":"https:\/\/www.bgs.ac.uk\/#organization"},"potentialAction":[{"@type":"SearchAction","target":{"@type":"EntryPoint","urlTemplate":"https:\/\/www.bgs.ac.uk\/?s={search_term_string}"},"query-input":"required name=search_term_string"}],"inLanguage":"en-GB"},{"@type":"Organization","@id":"https:\/\/www.bgs.ac.uk\/#organization","name":"British Geological Survey","url":"https:\/\/www.bgs.ac.uk\/","logo":{"@type":"ImageObject","inLanguage":"en-GB","@id":"https:\/\/www.bgs.ac.uk\/#\/schema\/logo\/image\/","url":"https:\/\/www.bgs.ac.uk\/wp-content\/uploads\/2020\/03\/BGS-logo-large.png","contentUrl":"https:\/\/www.bgs.ac.uk\/wp-content\/uploads\/2020\/03\/BGS-logo-large.png","width":250,"height":104,"caption":"British Geological Survey"},"image":{"@id":"https:\/\/www.bgs.ac.uk\/#\/schema\/logo\/image\/"}}]}},"_links":{"self":[{"href":"https:\/\/www.bgs.ac.uk\/wp-json\/wp\/v2\/pages\/25269"}],"collection":[{"href":"https:\/\/www.bgs.ac.uk\/wp-json\/wp\/v2\/pages"}],"about":[{"href":"https:\/\/www.bgs.ac.uk\/wp-json\/wp\/v2\/types\/page"}],"author":[{"embeddable":true,"href":"https:\/\/www.bgs.ac.uk\/wp-json\/wp\/v2\/users\/2"}],"replies":[{"embeddable":true,"href":"https:\/\/www.bgs.ac.uk\/wp-json\/wp\/v2\/comments?post=25269"}],"version-history":[{"count":42,"href":"https:\/\/www.bgs.ac.uk\/wp-json\/wp\/v2\/pages\/25269\/revisions"}],"predecessor-version":[{"id":74098,"href":"https:\/\/www.bgs.ac.uk\/wp-json\/wp\/v2\/pages\/25269\/revisions\/74098"}],"up":[{"embeddable":true,"href":"https:\/\/www.bgs.ac.uk\/wp-json\/wp\/v2\/pages\/3863"}],"wp:featuredmedia":[{"embeddable":true,"href":"https:\/\/www.bgs.ac.uk\/wp-json\/wp\/v2\/media\/28249"}],"wp:attachment":[{"href":"https:\/\/www.bgs.ac.uk\/wp-json\/wp\/v2\/media?parent=25269"}],"wp:term":[{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/www.bgs.ac.uk\/wp-json\/wp\/v2\/tags?post=25269"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}